A roll mill of the aforesaid type may be apprehended for instance from DE-A-39 15 320. In this case each grinding roll contains a basic roll body and a segment which is composed of a plurality of individual segments and is braced with the basic roll body. These segments of the roll shell consist essentially of a hard cast material and transversely extending plates made from a softer material which are cast into it. Since these cast-in plates wear rather more, even after very short grinding operation, than the chill cast material of the roll shell, corresponding grooves form on the surface of this roll shell which lead to profiling of the surface.
By the provision of surface profiling on the roll shell, an undesirable relative movement, i.e. slipping, sliding or flowing, between the roll surface of both rolls and the delivered material for grinding should be prevented during operation of the roll mill.
The object of the invention is to improve a roll mill in such a way that with relatively simple manufacture the rolls of this roll mill have a particularly good nip action for the feed material to be comminuted and at the same time have a particularly wear-resistant shell surface.
It is already known that the wear-resistant surface of a roll shell can be formed in such a way that in a deposit welding process ductile metal buffer layers and hard armoured layers are welded one above another so that they alternate several times radially when viewed from the inside outwards (cf. DE-C-38 43 173). However, there are limits to the thickness of these armoured layers.